With planetside 2 in my opinion catering more for the solo casual player the prowler does what it does, a one man army. A 2 or 3 man prowler is fun but only if you have friends to communicate with, and if you don't your forced to interact over a poor VOIP. But if your on your own and Timmy aged 5 jumps in your gunner seat and starts messing about / being a really crap gunner / taking on more then he can chew, is it really fun for you to just - sit there and be his own personal chauffeur? while some guy you don't know gets kills? Hes happy when the tank explodes - he has not lost 300 in resources, hes just had a blast! at your expense.
Of course having a crew tank will cut the amount of tank spam, but it could be an annoyance to get gunners, it'd require more communication alot of spam and mic spam to just get an armor push going (unless your with an outfit/squad of people who are on comms/chat etc)
I honestly think, even though i approve of crew tanks - planetside will turn into MMOFPS BUMPER CARS single man tanks having to ram enemy vehicles because hes just spawned a tank on his lonesome. XP variables between gunner/driver/top gunner need to be adjusted so its fair and worth it.
The only REAL solution i can think of is having a one man tank certificated, as in you have to cert up to being able to man a tank on your own - like, the lore could be "adding outloaders" or "remote controlled turret". Just to justify having a tank to yourself. Or they add one man as it is now but with negative effects over a crewed tank as in, slower turn rate of turret - slower reload - movement etc whereas a fully crewed vehicle is more optimal in its performance.
Having a crewed tank is fun when your with friends, a tank of greenies is a disaster on tracks.